Macroinvertebrate assemblage variations among aquatic habitat types across the arid Central Andes (Northwest Argentina)

Abstract

Andean macroinvertebrate diversity, habitat association and trophic structure. The Central Andes harbour globally unique species due to its complex topography, altitude gradients, and mountain orientations. Puna and High-Andean ecoregions of Argentina, part of the Central Andes, are among the world's driest areas. Despite the recognized importance for biodiversity of the scarce Andean aquatic ecosystems, knowledge about their invertebrate fauna remains limited. The objective of this study was to identify the benthic macroinvertebrate diversity associated with the diverse types of water bodies and their water quality characteristics in high altitude environments. Four aquatic habitat types were defined based on characteristics of their water flow: rivers and streams (RS, lotic), peatlands (P, minimum current flow), shallow salty pool (SSP, lentic) and shallow brackish lagoons (L, lentic). Significant differences were detected in conductivity (EC), and dissolved oxygen (DO) between aquatic habitat types. Ninety-five taxa and 4 phyla were registered: Arthropoda, Nematoda, Mollusca and Annelida. Insecta class represented 83% of the total richness of arthropods, being Diptera dominant with 47 taxa, followed by Coleoptera and Ephemeroptera. Richness was explained by water flow, DO and EC. Taxonomic composition differed between aquatic habitat types. Collector-gatherers and predators were dominant, indicating a dependence on the shore vegetation and hydrophytes.